I saw the same improvement with my few trays of seedlings, but I "cleaned up my act" in several ways at the same time so I can't say which change of habits helped the most.
- watering with dilute hydrogen peroxide (very dilute)
- putting a thin layer of coarse bark chips on top of the seedling mix so the surface was always dry
- replacing
very fine horribly water-retentive & badly aerated cheap peaty-dusty seedling mix with ProMix plus added re-re-screened pine bark "grit"
- occasionally ran a small fan
- continued trying to over-water less
Those (all at about the same time) cured my damping off. I think it was mostly using MUCH faster-draining / better-aerated mix that helped.
But later I figured out a convenient way to bottom-water, which might have accomplished most of that by itself.
Over-watering much less, all by itself, might have the same benefits, but I'll probably never know because it seems to remain beyond my self-control.
http://garden.org/ideas/view/R...
